(a) Field of the Invention
The present invention relates to an information detection device and an information detection display device, and in particular, to an information detection device and an information detection display device including a light sensor.
(b) Description of Related Art
A device for detecting position information or touch information of a selected position in a predetermined area detects the information using a detection of a resistance value or light variation. The former includes a plurality of resistive lines disposed on lower and upper substrates and extending vertically or horizontally. The resistive lines contact each other by external stimulus and vary the resistance thereof. The device senses the variation of the resistance to find position information or touch information. In the light variation sensing system, light sensing units sensing the variation of an amount of light, or an amount of light having a predetermined wavelength is used to detect the position information or the touch information.
A device using the resistive method is usually formed on a transparent substrate and is easily combined with other display devices. A device using the variation of light or the variation of light having a predetermined wavelength usually includes light sensing units incorporated in a display device. The resistive method decreases the luminance of the display device and increases the thickness of the product, while the device using the variation of light having a predetermined wavelength requires an additional element for generating the light having the predetermined wavelength.
An information detection device and an information detection display device, which includes light sensing elements therein, but which requires no additional light generator, for obtaining position information and touch information from the variation of light is known. However, in the known device the output signals of the light sensing units vary depending on the deviation of characteristics of the light sensing units and depending on the wavelength of incident light. Furthermore, the light sensing units incorporated in the display device may also be affected by other elements in the display device. For example, the foregoing problems occur in display devices which include amorphous silicon as an information detection device. Since the display device can form both of thin film transistors and light sensing units using amorphous silicon, the incorporation of the light sensing units into the display device is easy. However, the light sensing units have characteristic variation due to the amorphous phase and thus they output signals different from each other for the same stimulus. In addition, when the light sensing units are disposed under color filter layers according to the characteristics of the display device, the light sensing units may receive different-color lights. When the light sensing units are sensitive to a predetermined wavelength range, the outputs of the light sensing units may be different depending on the colors represented by the color filter layers. In addition, the light sensing units may be affected by image data signals for displaying images such that the light sensing units output distorted signals.